1. Field of the Invention
The present invention relates to a pressure control apparatus for a stirling module, and in particular to an improved pressure control apparatus for a stirling module capable of controlling a pressure between a compression space and a bounce space by providing an improved pressure control apparatus, so that a high speed operation of a stirling module can be obtained.
2. Description of the Conventional Art
FIG. 1 shows a conventional stifling module. As shown therein, the conventional stirling module is provided with a driving casing 20 for encasing a driving section 10. Here, a predetermined portion of the driving section 10 is drivingly connected to a piston connection section 30a, integrally formed with a piston 30, by a pair of driving rods 40 so that a predetermined driving force is transferred from the driving section 10 to the piston 30 by the driving rods 40. A displacer rod hole 30b is vertically formed within the piston 30 and the piston connection section 30a. The driving section 10 is drivingly connected to a displacer 50 by a displacer connecting rod 60. Here, the displacer rod 60 slidably reciprocates along the displacer rod hole 30b. The piston 30 and the displacer 50 are encased by a cylinder inner wall 80 of a cylinder 70. A heater 90 is disposed on the top of the cylinder 70 for receiving heat from the portion over the top of the cylinder 70. A regenerator 100 which is disposed below the heater 90 is connected with the heater 90 for regenerating heat transferred from the heater 90. A cooler 110 is disposed below the regenerator 100 and connected with the regenerator 100.
Meanwhile, inside the cylinder 70, an expansion space 120 is formed between the upper surface of the displacer 50 and the heater 90. A compression space 130 is formed between the bottom of the displacer 50 and the upper surface of the piston 30. A bounce space 140 is formed below the piston 30.
Here, the compression space 130 and the bounce space 140 are interconnected by a pressure control tube 150, on the intermediate position of which a check valve 160 is disposed for controlling the pressure flowing through the pressure control tube 150.
The operation of a conventional stirling module will now be explained with reference to FIG. 1.
To begin with, the piston 30 and the displacer 50 downwardly/upwardly reciprocate along the cylinder inner wall 80. In accordance with the above reciprocating operation of the piston 30 and the displacer 50, the expansion space 120, the compression space 130, and the bounce space 140 are alternately expanded and compressed. That is, the working gas in the expansion space 120 is expanded when the displacer 50 moves downwardly. At this time, the working gas in the expansion space 120 becomes cooled. The cooled gas receives heat from the outside of the top of the heater 90. That is, the heat contained in the working gas is eliminated by the regenerator 100 and radiated toward the outside of the cylinder 70 by the cooler 110. The working gas not containing heat flows into the compression space 130 through a predetermined path (not shown) formed on a predetermined portion of the cylinder inner wall 80. Thereafter, when the displacer 50 moves downwardly, the working gas in the compression space 130 flows into the expansion space 120 again through the same path as the working gas flows into the compression space 130 that is, through the cooler 110, the regenerator 100, and the heater 90 in order. During the above operation, a predetermined level of pressure of working gas should be maintained between the compression space 130 and the bounce space 140 by controlling the check valve 160 disposed on the pressure control tube 150.
However, the conventional stirling module has disadvantages in correctly maintaining the pressure between the compression space and the bounce space. That is, since the pressure control tube which is relatively lengthy is connected between the compression space and the bounce space, more correct controls of the pressure therebetween cannot be obtained. In addition, since the pressure control tube is connected to be exposed to the outside of the cylinder, the stirling module is bulky.